New COVID-19 Variant NB.1.8.1 Linked to China Outbreak Reaches U.S.
Health authorities in the United States have detected multiple cases of the new COVID-19 variant NB.1.8.1, which has been linked to a sharp rise in infections across China and parts of Asia. The Centers for Disease Control and Prevention (CDC) identified the cases through its international airport screening program.
According to genomic sequencing data published on the GISAID database, the variant has been found in international travelers arriving at airports in California, Washington, Virginia, and the New York City area. The infections were reported between April 22 and May 12, 2025, and the travelers had recently visited countries including Japan, South Korea, France, Thailand, the Netherlands, Spain, Vietnam, China, and Taiwan.
U.S. States Begin Reporting Local NB.1.8.1 Cases
In addition to airport cases, domestic transmissions have been confirmed in Ohio, Rhode Island, Hawaii, California, and Washington state. Some of these cases date back to late March and early April 2025.
The CDC has acknowledged these developments and confirmed that it is maintaining regular communication with global health agencies.
- “CDC is aware of reported cases of COVID-19 NB.1.8.1 in China and is in regular contact with international partners,” a spokesperson said.
— CDC Official Statement
At this stage, there are not enough NB.1.8.1 samples in the U.S. for the variant to be featured on the CDC’s official COVID-19 variant tracker.
Is NB.1.8.1 New Covid Variant More Dangerous or Contagious? What We Know So Far
The NB.1.8.1 variant is a descendant of the XDV lineage and is currently the dominant strain in China. Although no evidence suggests it causes more severe illness, researchers in China indicate that it has a stronger binding affinity to human cells, potentially making it more transmissible.
Officials in Hong Kong and Taiwan have reported a spike in hospital visits and admissions due to the variant. In response, authorities have reinstated mask mandates on public transport and begun stockpiling vaccines and antiviral medications.
For official travel and health advice for the Asia-Pacific region, visit the U.S. State Department Travel Advisories:
travel.state.gov
Fall COVID-19 Booster Shots May Target New Variant
The rise of NB.1.8.1 was a key topic at a recent meeting of the U.S. Food and Drug Administration (FDA) advisory panel. Vaccine manufacturers Pfizer and Moderna proposed updating the fall booster shots to target LP.8.1, another descendant of the JN.1 variant that may also provide cross-protection against NB.1.8.1.
- “The LP.8.1 vaccine has the highest titers against LP.8.1, which is dominant in the U.S. and cross-neutralizes other circulating variants, including NB.1.8.1,” said Moderna’s Darin Edwards.
The panel unanimously recommended that this year’s vaccines should target a JN.1 subvariant, although members were split on whether to revise the formula from last season.
For FDA vaccine updates and public health guidance, visit:
FDA COVID-19 Vaccines
COVID-19 in 2025: A More Predictable Seasonal Pattern?
According to the CDC, COVID-19 cases in the U.S. have fallen to low levels, measured via emergency department visits and wastewater surveillance. Unlike previous years, this past winter didn’t bring a major “strain replacement,” though health officials remain cautious.
- “After five years, we’re seeing patterns settle into something more predictable,” said Dr. Natalie Thornburg, acting chief of the CDC’s respiratory virus division.
The U.S. has largely observed two seasonal surges: one in summer and another in winter.
For current U.S. COVID-19 data and safety recommendations:
COVID Data Tracker – CDC
Key Takeaways:
- The NB.1.8.1 variant is driving a significant COVID-19 surge in China and spreading internationally.
- Detected through CDC airport screenings and now in multiple U.S. states.
- While it may not be more severe, its transmissibility is higher than other strains.
- The FDA is reviewing whether to target new variants like LP.8.1 and NB.1.8.1 in the next vaccine booster rollout.
- CDC and FDA continue to monitor evolving patterns and advise seasonal vaccine strategies.
Stay Updated from Trusted Sources
- CDC Official COVID-19 Page
- FDA COVID-19 Vaccine Guidance
- Travel Advisories – U.S. State Department
- COVID-19 Data Tracker
- World Health Organization COVID-19 Updates
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